Apparatus for pitting a whole drupe with a pitting knife which removes the pit or stone by forcing it through the body of the drupe. The term xe2x80x9cdrupexe2x80x9d refers to a fleshy fruit or vegetable such as a peach, plum, date, cherry, avocado or olive, usually having a single hard stone (or xe2x80x9cpitxe2x80x9d) that encloses a seed. More particularly, the invention provides at least one knife having a novel structure designed to provide a method for removing undesirable contaminants from within a generally axial passage left when a drupe is pitted. Such contaminants include the eggs of an insect such as a moth, or larvae of the insect, or the excretions of the larvae left during the period of their development, until the larvae can leave as a moth. These contaminants are not removed from within the passage formed by currently available or known pitting machines.
Machines which automatically pit a drupe have laid the foundation for an agribusiness which makes it possible for a person with even less than average income to enjoy fruits and vegetables which would otherwise be consumed only by the wealthy. Such machines are the subject of U.S. Pat. Nos. 2,157,518; 2,219,832; 2,630,205; and 2,688,352 to Ashlock, Jr.; of U.S. Pat. Nos. 3,153,473; and 3,556,281 to Margaroli et al.; and of U.S. Pat. Nos. 4,090,439 and 5,577,439 to Chall et al. and Cimperman et al., inter alia. Such machines have successfully achieved in the U.S. what is still done manually in countries where human labor is relatively inexpensive.
In the aforementioned pitting machines, a pitting knife or an assembly of plural pitting knives in a pitting head, cuts through the skin and flesh of the drupe being pitted, ejects the stone, and is then retracted leaving a substantially central passage in the drupe.
When a moth chooses a drupe to nurture its progeny, it lays its eggs on or near the drupe, typically on its upper surface. The eggs progress to the larva stage.
The time it takes an egg to get the larva stage typically corresponds uncannily to the period during which the drupe ripens. As the drupe ripens, a portion of its skin immediately surrounding its stem tends to pull away from the stem and at some stage, may do so, leaving a narrow passage through which a larva burrows its way into the flesh of the ripe drupe. The larva feeds on the ripe flesh of the drupe, and as the larva matures, its excretions, referred to as xe2x80x9cfrassxe2x80x9d, build up within the now contaminated drupe. When the contaminated drupe is harvested and pitted, the frass, if not the larva itself, is left behind in the passage within the pitted drupe because a pitting knife cannot remove the frass even if it successfully ejects the larva with the pit.
United States Standards for Grades of Dates specifies a defect when an unacceptable percentage of dates are xe2x80x9caffected by insect infestationxe2x80x94presence of dead insects, insect parts, or excreta xe2x80x9cfrassxe2x80x9d (no live insects are permitted).xe2x80x9d
A typical harvest may include from relatively few, to an economically disastrous percentage of contaminated fruit, and the extent of contamination can only be estimated by inspecting a large number of individual fruits. To date, when contamination is extensive, contaminated fruit has been disposed of as garbage, because there is no economical method of decontaminating the fruit. Worse, since it is currently impractical to sort contaminated fruit from uncontaminated fruit, marketable fruit is discarded along with the contaminated fruit.
When contamination is not extensive, the problem of removing the contaminants from within a pitted drupe has been addressed, unsuccessfully for the most part, by soaking the fruit in water, or passing the pitted fruit under a cascading stream of water, with the faint expectation that some of the water will enter the pit-free passage and flush away the frass. Besides being only marginally effective, both methods result in dissolving or otherwise sacrificing an unacceptably large portion of a fruit, such as a date or a prune, which typically has a relatively high water-soluble sugar content.
A pitting knife is usually made from hard stainless steel. Typically, plural pitting knives are mounted in a knife assembly held within the confines of a pitting head which houses the driving mechanism for timing and thrusting the knives into rows of fruit individually held in chucks, which are in turn, mounted on carriers carried by a conveyor belt. One does not expect to use a pitting knife for any purpose other than its designated purpose. One does not consider boring a pitting knife. Nevertheless, this invention does so; and thereby provides for contacting the walls of the passage of a pitted drupe with a decontaminating quantity of a decontaminant fluid, thus providing an effective solution to the problem of drupes internally contaminated with contaminants such as xe2x80x9cfrassxe2x80x9d.
It has been discovered that a pitting knife for a drupe may be provided with a longitudinal bore through which a decontaminant or cleansing fluid is discharged in a generally radial direction (relative to the longitudinal axis of the knife) to cleanse a pitted drupe. Use of the fluid during pitting has the added benefit of minimizing build-up of particles and remnant pieces of fruit adhering not only to portions of the pitting head but also to the chucks of fruit holders carried by the conveyor.
It is therefore a general object of this invention to provide an elongated pitting knife having a longitudinal bore and at least one generally radially extending bore in open communication with the axial bore and the knife""s outer surface; and means for supplying an effective quantity of decontaminant fluid to the axial bore, the fluid being under sufficient pressure to be ejected generally radially from the knife so as to contact the walls of the pitted passage.
It is a specific object of this invention to provide an assembly of plural knives each having an axial bore; the knife essentially simultaneously pits plural drupes to leave a pitted passage in each, and cleanses the passage; the assembly is connected with a means for supplying a decontaminant fluid to the knives; the fluid flushes each passage with sufficient cleansing fluid to remove contaminants from the passage.
It is also a specific object of this invention to provide (i) an assembly of plural conventional pitting knives which together first pit drupes to leave a pitted passage in each, and, (ii) an assembly of cleansing rods positioned after the assembly of pitting knives, which cleansing rods supply sufficient decontaminant fluid discharged under sufficient pressure to contact the walls of the passage left by the ejected drape and cleanse them. xe2x80x9cCleansing rodsxe2x80x9d are longitudinally-bored pitting knives having the primary function of providing cleansing fluid, rather than a cutting function. Cleansing rods are so termed, rather than xe2x80x9ccleansing knivesxe2x80x9d, to emphasize the cleansing function, and to distinguish over xe2x80x9cpitting and cleansing knivesxe2x80x9d which also have a cleansing function. Such sequential pitting and cleansing may be accomplished in a single pitting head, or in multiple pitting heads arranged serially along the path of the conveyor for the carriers. Alternatively, in another sequential operation, a first set of plural rows of pitting and cleansing knives may be succeeded by a second set of plural rows of cleansing rods the function of which is to provide a moisture-removing gas (xe2x80x9cdrying gasxe2x80x9d) from within pitted and cleansed passages. The cleansing rods thus function as xe2x80x9cdrying rodsxe2x80x9d. As before, the pitting and cleansing knives, and drying rods, may be mounted in a single assembly in a single pitting head, or for sequential operation, in two assemblies in separate pitting heads.
It is another specific object of this invention to provide a method for decontaminating a drupe which is internally contaminated, comprising, inserting a pitting knife within the drupe, ejecting a pit from within the drupe leaving a passage therewithin, flowing a decontaminant fluid through the pitting knife, and, ejecting the fluid in a generally radial direction, to contact walls of the passage, thereby flushing out contaminants; the fluid may be a liquid, or a gas, or a mixture thereof; the liquid may be water or an aqueous decontaminant, e.g. a solution of hydrogen peroxide; the gas may be ozone.